Plasma levels of glial fibrillary acidic protein (GFAp) and neurofilament light chain protein (NfL) were measures in 47 COVID-19 positive patients and 33 age-matched controls at symptom onset and after a mean of 11.4 days. Patients were stratified for disease severity as mild (n = 20, i.e., not requiring hospitalization), moderate (n = 9, hospitalized and requiring oxygen therapy), and severe (n = 18, admitted to intensive care unit). Presence of MRI abnormalities was an exclusion criterion. As both biomarkers correlated with age, log10 concentrations at estimated geometric means at 70 years were compared between groups. Patients with severe COVID-19 had higher plasma concentrations of GFAp (p = 0.001) and NfL (p < 0.001) than controls, while GFAp was increased also in patients with moderate disease (p = 0.03). Neither plasma GFAp nor NfL changed longitudinally in patients with mild or moderate disease. In the severe group a decrease in plasma GFAp was observed at follow-up (p < 0.01), while NfL levels increased longitudinally (p < 0.01). The authors suggest that astrocytic activation is an early marker, which might be common in moderate and severe stages, while plasma NfL increase reflects a progression to neuronal injury in severe cases.
doi: 10.1212/WNL.0000000000010111